Forehead support for a facial mask

ABSTRACT

A forehead support ( 10 ) for a respiratory mask ( 14 ). The forehead support ( 10 ) includes a pair of arms ( 22 ). The arms ( 22 ) are each adapted to locate a forehead cushion ( 30 ). The arms ( 22 ) are also adapted to pivot relative to each other. The arms ( 22 ) are also selectively lockable at two or more angular positions relative to each other. The forehead support ( 10 ) can thus be adjusted to suit the facial topography of the wearer of the respiratory mask ( 14 ).

FIELD OF THE INVENTION

The present invention relates to a forehead support for a facial maskused to supply breathable gas to a wearer's airways.

The invention has been developed primarily for use in supporting a nasalmask used in Continuous Positive Airway Pressure (CPAP) treatment of,for example, Obstructive Sleep Apnea (OSA) and other ventilatoryassistance treatments such as Non-Invasive Positive Pressure Ventilation(NIPPV) and will be described hereinafter with reference to thisapplication. However, it will be appreciated that the invention is notlimited to these particular uses and is also suitable for use with, forexample, full-face (ie. nose and mouth) masks.

BACKGROUND TO THE INVENTION

CPAP treatment is a common emeliorative treatment for breathingdisorders including OSA. CPAP treatment, as described in U.S. Pat. No.4,944,310, provides pressurised air or other breathable gas to theentrance of a patient's airways at a pressure elevated above atmosphericpressure, typically in the range 4-20 cm H₂O.

It is also known for the level of treatment pressure to vary during aperiod of treatment in accordance with patient need, that form of CPAPbeing known as automatically adjusting nasal CPAP treatment, asdescribed in U.S. Pat. No. 5,245,995.

NIPPV is another form of treatment for breathing disorders which caninvolve a relatively higher pressure of gas being provided in thepatient mask during the inspiratory phase of respiration and arelatively lower pressure or atmospheric pressure being provided in thepatient mask during the expiratory phase of respiration.

In other NIPPV modes the pressure can be made to vary in a complexmanner throughout the respiratory cycle. For example, the pressure atthe mask during inspiration or expiration can be varied through theperiod of treatment.

Typically, the ventilatory assistance for CPAP or NIPPV treatment isdelivered to the patient by way of a nasal mask. Alternatively, a mouthmask or full face mask or nasal prongs can be used. In thisspecification any reference to a mask is to be understood asincorporating a reference to a nasal mask, mouth mask, full face mask ornasal prongs.

In this specification any reference to CPAP treatment is to beunderstood as embracing all of the above described forms of ventilatorytreatment or assistance.

A CPAP apparatus broadly comprises a flow generator constituted by acontinuous source of air or other breathable gas such as a hospitalpiped supply or a blower. In the latter case, an electric motor drivesthe blower and is typically controlled by a servo-controller under thecontrol of a microcontroller unit. In either case, the gas supply isconnected to a conduit or tube which in turn is connected to a patientnasal or full-face mask which incorporates, or has in close proximity,an exhaust to atmosphere for venting exhaled gases. Examples of priorart nasal masks are shown in U.S. Pat. Nos. 4,782,832 and 5,243,971.

The supply conduit delivers gas into a chamber formed by walls of themask. The mask is normally secured to the wearer's head by straps. Thestraps are adjusted to pull the mask against the face with sufficientforce to achieve a gas tight seal between the mask and the wearer'sface.

A problem that arises with the use of the existing masks is that inorder for the straps to be tight, the mask is compressed against thewearer's face and may push unduly hard on the wearer's nose.Additionally, the mask may move around the wearer's face. Thus, therehas been hitherto provided a forehead support, which provides a supportmechanism between the mask and the forehead. This forehead supportprevents both the mask from pushing too strongly against the wearer'snose and/or facial region as well as minimising movement of the maskwith the addition of a contact point between the mask and the wearer'shead thereby reducing uncomfortable pressure points. Additionally, theforehead support can be arranged to prevent the gas supply conduit fromcontacting the wearer's forehead or face.

Forehead supports with a single cushion and a single contact point orthe forehead are known.

The applicant's U.S. patent application Ser. No. 09/008,708 relates to asubstantially rigid one-piece forehead support having a pair of foreheadcushions mounted at each outer end of the support. This forehead supportis connected to the top of a facial mask and includes an adjustablemechanism to allow the spacing between the top of the facial mask andthe forehead support to be altered between predetermined positions tothereby alter the angle of the mask relative to the wearer's head tosuit the wearer's facial topography.

It is an object of the present invention to provide an alternate form offorehead support.

SUMMARY OF THE INVENTION

Accordingly, in a first aspect, the present invention provides aforehead support for a respiratory mask, said forehead support includinga pair of arms, wherein: the arms are each adapted to locate a foreheadcushion; the arms are adapted to pivot relative to each other; and thearms are selectively lockable at two or more angular positions relativeto each other.

In a second aspect, the present invention provides a respiratory maskassembly comprising a respiratory mask and a forehead support, saidforehead support including a pair of arms, wherein: the arms are eachadapted to locate a forehead cushion; the arms are adapted to pivotrelative to each other; and the arms are selectively lockable at two ormore angular positions relative to each other.

As the angle between the arms adjacent to wearer's forehead is decreasedor increased the distance between the forehead and the extension of therespiratory mask is increased or decreased respectively, therebyaltering the angle of the respiratory mask relative to the wearer'sface.

The arms are preferably also adapted to each pivot relative to therespiratory mask.

Preferably, each of the arms include a cylindrical recess adapted topivotally receive a cylindrical boss provided on the respiratory mask.

The respiratory mask preferably includes an extension adjacent andabove, in use, the wearer's nose on which the cylindrical boss isprovided.

Desirably, one of the arms includes a tongue adapted to be received inone of at least two grooves provided on the other of the arms so as tolock the arms at one of two or more predetermined said angularpositions.

The tongue is preferably provided on a flexible member which is adaptedto permit the tongue be moved out of engagement with the grooves bymanual manipulation of the member.

The forehead cushions are desirably located on the outer ends of thearms.

The arms preferably also include means to connect a head strap thereto.

The respiratory mask preferably also includes means to connect a headstrap thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way ofexamples only, with reference to the accompanying drawings in which:

FIG. 1 is a front perspective view of a first embodiment of a foreheadsupport according to the invention connected to a nasal mask;

FIG. 2 is an underside view of the forehead support shown in FIG. 1 withthe tongue of one arm free of engagement with the grooves of the otherarm;

FIG. 3 is an underside view of the forehead support shown in FIG. 1 withthe tongue and groove engaged at the first of four positions;

FIG. 4 is an underside view of the forehead support shown in FIG. 1 withthe tongue and groove engaged in the second of four positions;

FIG. 5 is an underside view of the forehead support shown in FIG. 1 withthe tongue and groove engaged at the third of four positions;

FIG. 6 is an underside view of the forehead support shown in FIG. 1 withthe tongue and groove engaged at the fourth of four positions;

FIG. 7 is an underside view of a second embodiment of the foreheadsupport according to the invention with the tongue of one arm free ofengagement with the grooves of the other arm;

FIG. 8 is an underside view of the forehead support shown in FIG. 7 withthe tongue and groove engaged at the first of four positions;

FIG. 9 is an underside view of the forehead support shown in FIG. 7 withthe tongue and groove engaged at the second of four positions;

FIG. 10 is an underside view of the forehead support shown in FIG. 7with the tongue and groove engaged at the third of four positions;

FIG. 11 is an underside view of the forehead support shown in FIG. 7with the tongue and groove engaged at the fourth of four positions;

FIG. 12 is an upper perspective view of the forehead support shown inFIG. 7; and

FIG. 13 is an lower perspective view of the forehead support shown inFIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 6 show a first embodiment of a forehead support 10 accordingto the present invention. As shown in FIG. 1, the forehead support 10 isadapted for connection to an extension 12 of a facial respiratory mask14 used to supply breathable gas to a wearer's airways. The mask 14includes an angled connector 16 which has a distal end 18 for connectionto a gas supply conduit (not shown) and a proximal end 19 for connectionto the mask 14. The connector 16 communicates the supplied gas from thegas supply conduit to the interior of the mask 14.

The extension 12 is positioned on top of the nasal mask 14 generallyadjacent and above the wearer's nose. It will be appreciated that thisis just one example of a facial mask that could be supported by theforehead support 10. For example, the forehead support also findsapplication in supporting fall-face (ie. nose and mouth) masks.

Forehead supports according to the invention can also be used withfacial masks in which the gas supply connector 16 is incorporated intothe mask in the general position of the extension 12. In this type ofmask, the supplied gas flows through or past the forehead support 12.

The mask 14 includes a pair of slotted connectors 20 to which arerespectively connected ends of a lower head strap (not shown) forsecuring the nasal mask to the wearer's head.

The forehead support 10 includes a pair of arms 22 pivotally mounted toeach other adjacent the extension 12. Each of the arms 22 includes aslotted connector 23 to which ends of an upper head strap 25 arerespectively connected (see FIGS. 3 to 6).

The arms 22 each include a cylindrical recess 24 which receives acylindrical boss 26 provided on the extension 12. As best shown in FIGS.2 to 6, the cylindrical recess 24 and boss 26 allow the arms 22 to pivotrelative to each other, and the extension 12 (and thus the mask 14),about axis 28. These figures also show the forehead support cushions 30that are mounted at the ends of each of the arms 22. Examples ofcushions 30 include solid foam sponges, silicone, stuffed pads, dualdurometer foams, single pads or multiple pads joined together. Thecushions 30 can be integrally moulded with the arms 22 or attachedthereto by clips or adhesives or the like.

Also as shown in FIGS. 2 to 6, the right hand side arm 22 (shown on theleft hand side as FIGS. 2 to 6 are underside views) includes a flexiblemember 32 which has a tongue 34 on its distal end. The member 32 has afirst part 36 and a second part 38 which are bridged by a brace 40. Theleft hand side arm includes a generally arcuate shaped boss 41 havingfour grooves 42. It will be appreciated that four grooves is merelypreferable and that only two or more grooves are required. It will alsobe appreciated that the flexible member 32 can be on the left hand sidearm 22 and the boss 41 can be on the right hand side arm 22.

The arms are constructed from a plastics material, such aspolycarbonate, which allows the member 32, when pressed in the generaldirection of arrow 43, to be flexed relative to the arm 22 upon which itis mounted to release the tongue 34 from engagement from one of thegrooves 42 to allow angular adjustment between the arms 22. Releasingthe member 32 biases the tongue 34 towards the grooves 42. When thetongue 34 and one of the grooves 42 are aligned, as is shown in FIGS. 3to 6, the tongue 34 engages one of the grooves 42. When the tongue 34 isengaged with one of the grooves, the arms 22 are locked against pivotalmovement therebetween at a predetermined angle.

The tongue 34 has a radiused leading corner 35 and a similar radius isprovided on the corresponding corner 37 of each of the grooves Theleading corner 35 and corresponding corners 37 can also be angled. Whenthe arms 22 are pushed towards each other in a direction reducing theangle therebetween, the corner 35 causes the tongue 34 to ride up out ofengagement with the slot and fall into engagement with the next slot.This allows the angle between the arms 22 to be quickly adjusted in aratchet type fashion.

FIGS. 3 to 6 respectively show the tongue 34 engaged in the first,second, third and fourth of the four grooves 42. These figures also showa forehead represented by line 44. The distance between the front of theforehead 44 and the axis 28 is indicated by the distance A. FIGS. 3 to 6show that the distance A increases or decreases as the angle between thearms 22 adjacent the forehead 44 is decreased or increased respectively.

The extension 12 of the nasal mask 14 is connected to the foreheadsupport 10 generally in the region of the axis 28. Consequently, as thearms are pivoted towards each other the distance A is increased. Thissuits wearers with relatively high nasal regions and relatively lowforeheads. Conversely, as the arms 22 are pivoted away from each otherthe distance A is decreased. This suits wearers with relatively lownasal regions and relatively high foreheads.

In this way the forehead support 10 advantageously allows the mask 14 tobe positioned to comfortably suit the particular topography of thewearer's face by adjusting the angle of tilt of the mask 14 relative tothe wearer's face. As examples, the position of arms 22 in FIG. 3 wouldbe more suitable for use with a wearer having a protruding or bulbousforehead whilst the position of the arms 22 in FIG. 6 would be moresuitable for use with a wearer having a shallow forehead or protrudingcheeks or nose.

The curved shape of the cushions 30 allows them to effectively “roll”over the wearer's forehead during angular adjustment of the arms 22.

Further, as the arms 22 can also pivot relative to the mask 14, then theforehead support 10 is also able to better fit wearers whose foreheadsare not symmetrical about the front-to-rear centreline of their head.

Further, the forehead support advantageously allows the angle betweenthe arms to be adjusted using only one hand. The ease of adjustment ofthe arms also makes the forehead support particularly suitable for useby sick, weak or one-armed wearers.

FIGS. 7 to 13 shown a second embodiment of a forehead support 50according to the present invention. Like reference numerals to thoseused in describing the first embodiment will be used to indicate likefeatures in the second embodiment

The forehead support 50 is similar to the forehead support 10 shown inFIGS. 1 to 6 except the flexible member 32 is mounted to the right handarm 22 and has a cantilever configuration. To increase resilience, themember 32 is bent back on itself into a U-shaped configuration toresiliently bias it against the boss 41 provided on the left arm 22. Themember 32 also includes a protruding portion 54 which, when pressed inthe general direction of arrow 56, causes the tongue 34 to move out ofengagement with one of the to grooves 42 to allow angular adjustmentbetween the arms 22. Releasing the member 32 biases the tongue 34towards the grooves 42. Engagement between the tongue 34 and one of thegrooves 42 occurs when they are aligned.

Although the invention has been described with reference to a specificexample, it will be appreciated by those skilled in the art that theinvention may be embodied in many other forms.

As an example, the forehead support can include means to resilientlybias the arms relative to one another such that they increase ordecrease their angle relative to one another when the tongue isdisengaged from one of the slots. Also, in the embodiments describedabove the angle between the arms can be changed independently of theangle between the mask and the arms. However, in an alternativeembodiment, the arms can be adapted to simultaneously change theirrelative angle, thereby maintaining a symmetrical position relative tothe mask. Further, the tongue and grooves of the second embodiment canhave the radiused corners of the first embodiment.

I claim:
 1. A respiratory mask assembly comprising a respiratory maskand a forehead support, said forehead support including a pair of arms,wherein each of the arms has a surface adapted to directly contact asurface of a forehead cushion; the arms are adapted to pivot relative toeach other; and the arms are selectively lockable at two or morepredetermined angular positions relative to each other.
 2. Therespiratory mask assembly as claimed in claim 1, wherein the arms arealso adapted to each pivot relative to the respiratory mask.
 3. Therespiratory mask assembly as claimed in claim 1, wherein each of thearms include a cylindrical recess adapted to pivotally receive acylindrical boss provided on the respiratory mask.
 4. The respiratorymask assembly as claimed in claim 3, wherein the respiratory maskincludes an extension adjacent and above, in use, the wearer's nose onwhich the cylindrical boss is provided.
 5. The respiratory mask assemblyas claimed in claim 1, wherein one of the arms includes a tongue adaptedto be received in one of at least two grooves provided on the other ofthe arms so as to lock the arms at one of said two or more predeterminedangular positions.
 6. The respiratory mask assembly as claimed in claim5, wherein the tongue is provided on a flexible member which is adaptedto permit the tongue be moved out of engagement with the grooves bymanual manipulation of the member.
 7. The respiratory mask assembly asclaimed in claim 1, wherein the forehead cushions are located on outerends of the arms.
 8. The respiratory mask assembly as claimed in claim1, wherein the arms also include means to connect a head strap thereto.9. The respiratory mask assembly as claimed in claim 1, wherein the